This invention relates to an endoscope apparatus for observing an inside wall of a blood vessel.
If an inside wall of a blood vessel could be observed through an endoscope, it would be of great help to diagnosis and treatment of diseases such as myocardial infarction, cerebral thrombosis. However, this is not an easy job to carry out because the view field of the endoscope is covered with blood in the blood vessel.
The present invention has been accomplished in view of the above situation. According to a first feature of the present invention, there is provided an endoscope apparatus for an inside wall of a blood vessel comprising (a) a side view endoscope including a main body portion, a flexible insert portion extending from the main body and a distal end constitutional portion disposed at a distal end of the insert portion, the insert portion being capable of being inserted into the blood vessel, the distal end constitutional portion being provided at a peripheral surface thereof with an illuminating window and an observing window, a light guide for transmitting an illuminating light to the illuminating window and an image guide for transmitting an imaging light which is made incident to the observing window being inserted into the insert portion, thereby enabling to observe the inside wall of the blood vessel located in a radial direction of the distal end constitutional portion, (b) a balloon for enclosing the distal end constitutional portion, at least a part of the balloon which covers the illuminating window and the observing window being transparent, (c) a flexible insert tube extending along the insert portion, an internal space of the distal end of the insert tube being in communication with a space between the balloon and the distal end constitutional portion, and (d) fluid feeding means connected to a basal end portion of the insert tube and adapted to feed a fluid to the balloon through the insert tube.
Owing to this feature, by expanding the balloon so as to be urged against the inside wall of the vessel, the inside wall of the blood can be observed.
According to a second feature of the present invention, there is provided an endoscope apparatus for an inside wall of a blood vessel, wherein, in addition to the first feature, the insert tube and the balloon are integrally continuous with each other thereby constituting a balloon catheter, the insert portion of the side view endoscope is inserted into the insert tube, a sealing is provided between the balloon catheter on the basal side and the side view endoscope, and a space formed between the insert tube and the insert portion serves as a flow passage for guiding the fluid to the balloon.
Owing to this feature, by inserting the insert portion into the balloon catheter and further into the blood vessel, the balloon can be expanded serving the space formed between the inner periphery of the insert tube and the outer periphery of the insert portion as a flow passage.
According to a third feature of the present invention, there is provided an endoscope apparatus for an inside wall of a blood vessel, wherein, in addition to the second feature, the balloon is transparent over its entire periphery, and the insert portion and distal end constitutional portion of the side view endoscope are rotatable with respect to the balloon catheter about an axis of the insert portion and the distal end constitutional portion.
Owing to this feature, the inside wall of the blood vessel can be observed over 360 degrees.
According to a fourth feature of the present invention, there is provided an endoscope apparatus for an inside wall of a blood vessel, wherein, in addition to the third feature, the distal end constitutional portion includes an extending shaft portion disposed on a more forward side rather than the illuminating window and the observing window and projecting in an axial direction, and the balloon is provided at its distal end with a shaft receiving portion for rotatably receiving the extending shaft portion.
Owing to this feature, the distance between the distal end constitutional portion and an observing part of the inside wall of the blood vessel, and thus the focal distance can be maintained constant irrespective of angle.
According to a fifth feature of the present invention, there is provided an endoscope apparatus for an inside wall of a blood vessel, wherein, in addition to the first feature, the distal end constitutional portion receives therein a pair of illuminating prisms for refracting the illuminating light delivered by the light guide towards the illuminating window and an imaging light prism for refracting the imaging light made incident to the observing window towards the distal end of the image guide, the pair of illuminating prisms being arranged in such a manner as to sandwich the imaging light prism therebetween.
Owing to this feature, illuminating light can be obtained from two sides of the observing part and there can be obviated such an inconvenience that one side of the observing part becomes dark and therefore, difficult to be observed.
According to a sixth feature of the present invention, there is provided an endoscope apparatus for an inside wall of a blood vessel, wherein, in addition to the fifth feature, the pair of illuminating prisms are arranged such that optical axes of the illuminating lights after refracted are intersected with each other on an optical axis of the imaging light before refracted.
Owing to this feature, the observing part can be illuminated more brightly.